A Tough Winter for Southern Bats: Tracking the Spread of WNS in Georgia

The winter bat monitoring season had an ominous start. Kevin Glenn of the National Speleological Society emailed in early February to say they had seen signs of white-nose syndrome on bats in Kingston Saltpeter Cave. I had been expecting to start hearing reports of bats with white fuzzy noses any day. But Kingston, in Bartow County, would be the farthest south the disease had ever been reported.

A tri-colored bat with white-nose at Black Diamond Tunnel in Rabun County. More photos available at WNS Surveys 2014.

On Feb. 22, Pete Pattavina with the U.S. Fish and Wildlife Service joined me for the Saturday survey with Kevin and his partner, Shannon. Kingston Saltpeter Cave has an interesting past, from its use as a dance hall to the mining of saltpeter for gunpowder. Our survey added to that history: We found the fungus that causes WNS on more than half of the 160-plus bats in the cave. And that was only the beginning.

We expected to see the fungus during a survey the next week at White River Cave in nearby Polk County. Normally, we count nearly 1,000 bats at White River. This year, helped by landowner Mason Rountree, Jackie Jeffery of DNR, Laci Coleman of EcoTech and a handful of other volunteers, we only saw about 80 bats. We had detected the fungus on one swab of the cave wall from last season but we hadn’t observed WNS. We didn’t this season, either.

So where were the bats? Mason told us the cave flooded last fall. We also noticed it was unusually warm. Our theory is that the flooding and possibly changes in the cave airflow caused conditions to be undesirable for bats.

Still, the cave is part of a nationwide survey to track the spread of the fungus. Swabs from bats and surfaces this year will be analyzed. We will also continue to monitor White River to see if the bats return.

Bad News at Black Diamond

The next Sunday, Regina Bleckley, owner of Black Diamond Tunnel in Rabun County, called. I could immediately tell she was upset. Earlier that day, she had seen a bat flying out of the tunnel, a possible sign WNS was affecting the hibernating bats. We had a survey scheduled for Black Diamond the following Tuesday. I told her maybe the bat had been disturbed and maybe not because of WNS. Unfortunately, soon after we arrived we confirmed her fears.

Jackie, Pete and Nikki Castleberry, of the Georgia Museum of Natural History, helped guide the boat through the tunnel. Black Diamond normally provides wintering habitat for 5,000 tri-colored bats on average, the largest known hibernaculum in the state. In 2013, we counted 5,517 bats. In this, the first year of WNS infection at the site, we counted only 3,472 and observed nearly 100 dead bats. Because the tunnel is flooded, it’s also unlikely dead bats would be detectable for long.

The cold weather this winter may have been partially responsible for the large drop in bat numbers at Black Diamond. However, if this decline continues, next year’s survey will be a difficult one.

The following week, Pete and I met with employees from Imerys to survey the Whitestone Marble Mines in Gilmer County. We counted fewer than 383 bats, compared to more than 500 last year. Some bats were infected with the fungus but many were too far away to determine if the disease was present. Visiting the marble mines is always an experience and many of these vast expanses of underground mazes are inaccessible to people due to safety concerns. Certainly they provide important winter refugia for bats, but they can’t escape the impacts from WNS.

From Hopeful to Tragic

Osbourn Cave on Black’s Bluff Preserve in Floyd County is owned by The Nature Conservancy. I surveyed Osbourn on March 12 with help from Dottie Brown of Ecological Solutions. White-nose wasn’t found at the cave in 2013 and it seems to have been spared for at least one more season. We counted more than 200 bats and all appeared healthy. The cave is very dry, a condition that might not be the best for the growth of Pseudogymnascus destructans, the fungus that causes WNS. Although not many bats use Osbourn Cave, with the declines observed so far it was good to see healthy bats. We can only hope they continue to escape the impacts of the fungus over the next few seasons.

Another survey on Saint Patrick’s Day led us to Howard’s Waterfall Cave, owned by the Southeastern Cave Conservancy. Jerry Wallace of the conservancy led the trip, with Jackie, Pete and Chris Coppola, of the Fish and Wildlife Service, also helping. Finding signs of WNS was no surprise. However, the number of bats had declined by about a third from last season.

It wasn’t a good start to a week of surveying the northwestern part of Georgia where WNS was first detected in the state in early 2013. But we couldn’t have predicted what we found the following day.

Sitton’s Cave at Cloudland Canyon State Park was the first site on state-owned land confirmed positive for white-nose, a confirmation made last year. This winter, a large survey team including Pete, Chris and Jimmy Rickard of the Fish and Wildlife Service, plus Jackie, Brian Nichols and Josh Purdy of DNR, headed into the cold, wet passage to see what WNS had done to the site in only a year. Silence told the story as the clicks from counters marking bats observed were few and far between.

We counted only 250 bats at Sitton’s. In 2012, the total exceeded 1,700. That’s a decline of 85 percent in two years. And unlike what we’d seen in other infected caves, there were no bat carcasses at Sitton’s. Only empty walls and silence.

A part of me wants to believe that the bats found another cave to use this winter and they’ll be back. But logic tells me that’s not true.

Spreading Farther South

The mystery of the missing White River Cave bats led me and volunteer Kevin Townsend to Deaton’s Cave in Polk County on March 20. This cave had not been surveyed before but was close to White River and we thought maybe the bats had moved there during the flooding.

Deaton’s is another cave that had been used for entertainment before air-conditioning made indoor summer activities more comfortable. A small stage built in the “dance hall room” is still there. Unfortunately, we only saw 66 bats and several showed signs of white-nose.

The crawl from the main room was flooded so if bats from White River had tried to winter there, they were trapped. Deaton’s now represents the farthest point south that WNS has been recorded in the U.S.

During the final week of surveys for the winter monitoring season, Jackie, Pete and I met Allen Padgett of Walker County’s Cave and Cliff Rescue Team at Anderson Springs Cave on Crockford-Pigeon Mountain Wildlife Management Area. Allen, a DNR retiree who once worked as area manager of the WMA, guided the crew into the cave.

Our count of tri-colored bats was almost double last year’s count, about 1,200 bats. Normally, I would be excited about a jump in numbers like this. But I have followed the trends from the beginning and I know this is part of a pattern seen over and over. We saw signs of WNS at Anderson Springs, and more bats near the entrance. Often when bats first become infected, they will move from inaccessible parts of the cave to areas along the survey route. This rise in numbers is likely only temporary.

Although the cave includes an excruciatingly cold crawl through a flooded passage, the formations at Anderson Springs make it one of my favorite to visit. But I’m already dreading next year’s survey. If bats in Georgia follow the same trends as those at infected sites farther north, the numbers at the cave will be much lower next year and likely even lower the following year.

The next day we visited Ellisons Cave and added Jimmy Rickard of the Fish and Wildlife Service and Sara Keys of Walker County Cave and Cliff Rescue to the survey team. Last year, we had seen WNS at Ellison’s, the first detections on the WMA with the most state-owned cave resources in Georgia. As expected, infection rates this year were higher. Live bat totals were down by about one-third and we counted some 60 dead bats. More bad news.

Facing the Expected

On our final day of surveys, a beautiful, exceptionally warm day at the end of March, Jackie and Jimmy joined me in Pettijohn’s Cave. Pettijohn’s is extensive in size and it’s the most heavily visited cave on Crockford-Pigeon Mountain WMA. We only survey a small portion of the cave, which doesn’t have many bats. But we did detect signs of WNS, a first for Pettijohn’s this season. The results seemed a fitting end to a winter filled with evidence of a killer bat disease that doesn’t seem to be slowing down.

On the long drive home from northwest Georgia, I reflected on what I had seen in the last few years. We started counting bats in Georgia when white-nose syndrome first began decimating bat populations in New York and Pennsylvania. We gradually added more sites to get better winter numbers as the disease spread rapidly down the Appalachian Mountains. I knew we would find the fungus in Georgia last year but I wasn’t prepared for how seeing the disease for the first time in my state would make me feel. This year, I thought I was prepared to see greater impacts. But, again, I wasn’t.

How could I prepare for watching bats disappear from caves where they have thrived for years?

It’s likely that in my lifetime I will never again see sites with thousands of hibernating bats. Will there even be places where there are hundreds? We don’t know. I’m holding onto the hope that next winter will be warmer and bats will do better in the South. Time will tell. For now, all we can do is watch and wait.